Not Applicable
The present invention relates generally to hearing test devices and more specifically to an infant hearing screener which uses distortion-product otacoustic emissions (DPOAE) to determine the function of the outer hair cells, which is an indication of middle-ear function. For example, the absence of DPOAE indicates a possible hearing loss.
The otacoustic emissions produced by a healthy ear are extremely small in magnitude. The emissions typically range from xe2x88x9210 db SPL to +20 db SPL. Any kind of extraneous noise introduced into the ear canal or measurement system can mask these emissions and give a false negative response. The microphone must have a very low internal noise level to discriminate the emissions from the system noise. All existing equipment for testing for DPOAE uses a probe which seals into the ear canal and is attached to the measurement equipment through a cable. This type of system is not practical in an infant screener for several reasons.
These reasons include the fact that an infant""s ear canal is very small, and as a result, it can be quite difficult to seal a probe into such a small canal. any pull on the probe from the attached cable can break the seal or pull the probe out of the canal. In addition, the time required to place a probe in the infant""s ear canal significantly slows down the testing process. Typically, the infant is asleep when the testing is performed so that movement is minimal. The process of putting the probe into the infant""s ear canal in a manner so that it stays for the duration of the test often wakes the infant which, of course makes the test difficult or impossible to perform.
While a hand-held screening device alleviates many of the above discussed problems, implementation of such a device has inherent problems which must be overcome to provide an effective hearing measurement device. One such problem results from the vibrational noise generated by the tester""s hand during the testing. This noise is transmitted through the device and into the microphone which prevents accurate measurements. Holding a conventional probe to the ear canal creates a noise level that completely masks any emissions that could otherwise be detected.
Another problem is the difficulty in achieving a consistent seal to the infant""s ear canal. Difficulty in maintaining the seal results from minor movements of the infant""s head and/or the tester""s hand.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with the present invention as set forth in the remainder of the present application with reference to the drawings.
The present invention is related to an hearing screener that uses distortion-product otacoustic emissions (DPOAE) to determine the function of the outer hair cells within the middle ear structure. The function of the outer hair cells is an indication of middle-ear function; the absence of DPOAE indicates a possible hearing loss.
In one embodiment, the screener is hand-held device that couples to the infant""s ear to perform DPOAE testing. The device creates tones and administers them to the ear canal through two receivers. The emissions are then picked up through a low-noise microphone, and analyzed by a built-in digital signal processor (DSP). The result is displayed on a liquid crystal display (LCD) and can be printed by infrared link to a separate hand-held printer.
Aspects of the present invention may be found in a hearing screener apparatus that comprises a housing, a testing probe operatively coupled to the housing, and one or more microphone(s). In one embodiment, the microphone has a noise floor substantially similar to an industry standard microphone when the housing is grasped by a user. In another embodiment, the microphone has a noise floor of at least approximately 15 dB lower when the housing is grasped by a user than when the testing probe is grasped by a user.
The microphone(s) may be mounted with the testing probe, for example, and the testing probe may be vibrationally isolated from the housing. In one embodiment, the testing probe is elastically coupled to the housing. In addition, the hearing screener apparatus may further comprise an isolation body elastically coupled between the testing probe and the housing. The hearing screener apparatus may also comprise an ear tip mounted on the testing probe for acoustically sealing the ear canal of a test subject.
These and other advantages and novel features of the present invention, as well as details of an illustrated embodiment thereof, will be more fully understood from the following description and drawings.